The present invention generally relates, in general to a computer system, and, more particularly, the invention relates to a method of management of a data transfer between storage systems in a computer system.
In recent years, in order to continue the processing in a computer system, even when a malfunction occurs in a storage system (hereinafter referred to as a “first storage system” or “primary storage system”) in the computer system, such as during a disaster, technology for replicating data recorded in the first storage system to another storage system (hereinafter referred to as the “secondary storage system”), which has been established at a remote location from the first storage system, is becoming important. Patent Document 1 (U.S. Pat. No. 5,170,480) discloses technology (hereinafter referred to as “synchronous remote data duplication”) for proceeding with the processing in the first storage system after the data is updated in the first storage system and after the data replication in the second storage system is confirmed.
Further, Patent Document 2 (Japanese Patent Laid-Open Publication No. H7-239799) discloses, in addition to the technology of synchronous remote duplication, technology for continuing the processing in the computer system only with the update of the first storage system, and replicating data in the secondary storage system asynchronous with the update of data in the first storage system (hereinafter referred to as “asynchronous remote data replication”).
Moreover, Patent Document 3 (Japanese Patent Laid-Open Publication No. 2004-259079) discloses, as a type of asynchronous remote duplication, technology in which the primary storage system stores the update information of data to be stored therein as a journal (update log), the primary storage system forwards this journal to the secondary storage system, and the secondary storage system updates the data stored therein in the same manner as the primary storage system by employing the forwarded journal.
Patent Document 4 (Japanese Patent Laid-Open Publication No. 2001-236258) discloses technology for transferring the computer system implementing asynchronous remote duplication to implement a synchronous remote duplication based on the information of a malfunction that has occurred.
The foregoing three types of remote duplications in accordance with conventional technology each have unique characteristics, and they are used according to the particular objective. Nevertheless, in accordance with conventional technology, once the mode of remote duplication to be executed with the system is determined, unless the administrator or the like stops the system and changes the mode, remote duplication is executed in the system based on the same mode. Here, with this technology, depending on the operating status of the system, there are cases where resources in the system will incur a waste.
For example, with the asynchronous remote duplication process disclosed in Patent Document 3, when an update of data in the first storage system is not conducted frequently, the storage extent secured for storing the journal will hardly be used, and the storage capacity used for such portion will be wasted.
Meanwhile, Patent Document 4 discloses technology for automatically changing the remote replication mode in the system for the purpose of preserving data in the system. Nevertheless, since no consideration is given to the effective use of resources in the system, even if the remote replication mode is merely changed using the technology disclosed in Patent Document 4, a waste of resources cannot be overcome.